Cyanamide is an important raw material for the production of chemicals, widely used in medicine, pesticides, plastics, fibers and other fields. The following are the manufacturing methods of cyanamide:
I. Lime Nitrogen Method
The lime nitrogen method is the main method of producing cyanamide at home and abroad. This method takes lime nitrogen as raw material, reacts with water vapor under heating conditions to produce cyanamide and calcium hydroxide. The reaction equation is as follows:
CaCN2 + 3H2O → 2H2CN2 + Ca(OH)2
The specific operation steps are as follows:
1. Crush the lime nitrogen to a certain particle size and mix it with water to form a paste.
2. The mixture is fed into the reactor and water vapor is passed through for heating reaction.
3. The reaction product is cooled, crystallized, centrifuged and dried to obtain the finished cyanamide product.
The method is mature and simple to operate, but the production process will produce a large amount of waste residue and waste gas, causing some pollution to the environment.
II. Electrolysis method
Electrolysis method is a more advanced cyanamide manufacturing method, through electrolysis of the solution containing cyanide ions, so that the cyanide ions oxidized on the anode to generate cyanamide. The specific operation steps are as follows:
1. The solution containing cyanide ions is fed into the electrolysis tank, and direct current is passed through to carry out electrolysis. The cyanide ions on the anode are oxidized to form cyanamide, and hydrogen gas is precipitated on the cathode.
3. By controlling the current and electrolysis time, a cyanamide product with high purity can be obtained.
This method has the advantages of high product purity and no waste residue and gas, but the equipment investment is larger and the energy consumption is higher.
Third, acrylonitrile method
Acrylonitrile method is a method of preparing cyanamide through the hydrolysis reaction of acrylonitrile. Specific operation steps are as follows:
1. Mix acrylonitrile and water, heat to a certain temperature, so that acrylonitrile hydrolysis to generate acrylamide.
2. The acrylamide then reacts with ammonia to form cyanamide and acrylonitrile.
3. The unreacted acrylonitrile and the generated cyanamide are separated by distillation, and the cyanamide product with high purity is obtained.
This method is simple and easy to operate, but the production process will produce certain wastewater and exhaust gas, which need to be effectively treated.
In summary, the above three methods can be used in the manufacture of cyanamide, but each method has its advantages and disadvantages and scope of application. In the actual production, the suitable method should be selected according to the specific situation, and the environmental protection management should be strengthened to ensure that the production process meets the environmental protection requirements.
